The Virtual World
Chapter Index
Introduction
History
Getting Connected
Browsers
Copyright
Search
Engines
HTML
Linking documents
Images
Newsgroups
Tables
Forms
Frames
Graphic crunching
The HistoryThe Internet started out as a response to fear. It was a positive response to a very negative set of actualities and possibilities.
Back in the early sixties we had a nasty state of affairs. The western world was divided rather sharply into The East and The West: The Communist Bloc and The Free World. Russia had, after the Second World War, grabbed into her political ambit all the countries of Eastern Europe to act as a buffer zone to protect her borders. The reasons for this go back to the beginning of the century and don't concern us here. But, suffice it to say, when the Americans, under the guise of the West's supposedly defence-oriented military arm, Nato, started putting military bases with heavy nuclear back-up into Turkey, right on the Southern borders of the Motherland, the politburo started to get exceedingly nervous.
One day we all learned that Mr Krushchev had been talking to Mr Castro in Cuba, and had arranged to have some holes dug in the good Cuban earth. The intent was to place a few ICBMs inside, ready to bang them off at the United States, just a few miles away - only as a precautionery gesture of course.
Kennedy and Krushchev starting swearing at each in good diplomatic language, while the rest of us battened down the hatches and prepared for World War Three. Every time the bell rang at the end of lessons, we thought that was it - four minutes to the end of time.
After a few weeks of stand-off and heavy words there was a backing down, and things began to go back to normal.
However, things did not go back to normal in the paranoid world that is the American military.
Supposing a missile hits a strategic telephone exchange. So, a few people can no longer talk to each other, big deal. However, what if a few strategic military computers can no longer talk to each other. That, my friend, is seriously heavy.
The protocols we now use to connect to various computers on the internet all owe their structure to the thinking that went into solving this major military concern of a lack of computer coordination during a nuclear attack.
The problem was solved in what appears on the face of it to be a very silly way. We will see as we go through this story that time and time again things are designed to operate in what appears to be a Heath-Robinson manner.
The design that the boffins came up with was simple, but relied on a somewhat old fashioned example: the post office.
Every letter gets to its destination because it has an address on its envelope. You can send three letters to the same address. You post one on friday from the office in London. Because you haven't finished the other two, you take them home. You finish them and post one in Hampshire on Saturday afternoon. The other you appear to have mislaid. Your wife has inadvertantly packed it, and takes it off to Paris with her on Sunday. Finding it as she unpacks in her hotel, she posts it in the nearest post box.
All three letters have gone from widely spaced letter boxes, and have been to different sorting offices. They all, we hope, end up at the right address. If a terrorist gang blows up one sorting office, or indeed, blows up sixteen, there will still be enough offices around the world to operate the system and the mail will get through.
Why can't we do the same with telephone messages? asked the boffins. And, indeed, they did. They invented packet switching, whereby the information arriving at a telephone exchange could be sent in packets each with the destination telephone number attached. That way, no matter how many exchanges along the way are blown to kingdom come, each little packet with its destination number attached to it can be routed to its final destination.
All this was not possible until the advent of digital sound. It is easy to chop up a series of numbers, not so easy to chop up sound. it is easy to add a digital address to digital sound. You are merely inserting a few numbers into a set of other numbers. It is not so easy to do that to physical sound.
We have here another apparent absurdity. We have computers that can crunch numbers and solve problems, scan information, and send it across the world, all much quicker than human beings can do it, and yet they do it in what appears to be an impossibly difficult way.
Instead of doing things sensibly and using the sophisticated numbering system that humans devloped over the centuries they use a very constricting system allowing only two actual numbers, zero and one.
Humans can represent the number 8 quite easily. In binary numbers it is far more unweildy. It comes out as 1000.
I'm sure you are all familiar with this, but briefly it goes as follows:
0
1
2
3
4
5
6
7
8
9
100
1
10
11
100
101
110
111
1000
1001
1010
You will note that on the left we have our system of numbering using a base of ten, and on the right the binary system using a base of two. Computers can only use two numbers, because they represent a switch being either on or off, there is no other state a switch can be in, so we can't have any more numbers, only more switches. In modern computers we have one hell of a lot of switches. (This could well change in the twentyfirst century when we start using biological carriers for messages.)
In our ten base system when we run out of digits we start using the same lot all over again. We just shunt them to the left. After 9 we run out of digits and have to go back to one again, but it is shunted to the left and has a zero after it: 10. We then go through the routine again until at 99 we run out of digits and have to do another left-shunt.
1
...9
10
11
...99
100
101
The only positive thing we can say about this unweildy system is that it works.
The only positive thing we can say about packet switching is that getting the phone system to work like the post office appears to work. It in fact, also saves time and resources because telephone capacity can be used more productively, with packets from different origins being packed into a digital tube in whatever order they appear at the router. There is, therefore, no redundant space on the cables.
We will come back to this digital point again shortly, but from a different direction.
The Physical State of the Internet
Let us look at the Internet in terms of a physical entity. This is probably only of limited value, but it is an approach that still appeals to pre-twentyfirst-century minds.
At home you probably have a single, stand-alone computer. You have certain programs and files on your hard disk. What you don't have on your disk you don't have access to, and that is that.
At work, or at college, you probably have a network of computers. There are dozens of machines all connected to wires in the wall, which route round to a room containing the server. This is a local area network or LAN. You have files on the computer in front on you, but there are also files on the server, and you can access those files as well.
You may belong to a major company or university that has several sites, maybe in different towns, or even in different countries. If each site has a network of computers, then they can all be connected by using the telephone cables, so you have computers from several different sites connected to each other by wires round the walls which are connected to a telephone cable which is then directly connected to the other site. This is a Wide Area Network, or WAN. Here you probably have access to the files on servers at each site.
For a WAN to work properly you need a permanent telephone link. It is no good having to use a dial-up telephone system. You must have a dedicated line that is used by the company alone, and this line is permanently open.
Take a few companies and colleges with systems like this and link them together, and you have the beginnings of the Internet. You merely need a few routing computers to handle traffic, much in the same way as a telephone exchange helps route phone calls to the right place.
In the early days of the internet there were only a few defence machines linked together. This was followed by a few universities. Gradually, the number of universities joining the system grew, and a few commercial sites joined in too. This soon became too much of a good thing for the defence establishments. They wanted to maintain their secrecy, and opted out of the system. And this was the state of affairs in the early seventies.
So you had a series of Wide Area Networks joined together by a few dedicated routing machines, all using a part of the telephone system.
This system has grown and grown to become the massive phenomenon that we now know as the Internet.
How it Looks Today
The Internet today (Winter 1997/8) consists of a large number of computers (the number is rising rapidly all the time, so the exact figure is somewhat irrelevant) that are permanently connected to each other using the telephone system. These computers consist of several different types. There are the universities, companies, and organisations such as local authorities, and government departments. There are shops like Amazon (which is vaunted as the world's largest book shop), newspapers and magazines, and supermarkets where you can buy your goods online and have them delivered by van the following day. And of course, there are the dirty pics brigade, all doing very nicely with their high tech sites, and low cut pics.
All of the above have permanent links set up so they are online 12 hours a day, 7 days a week, 365 days a year.
There are also companies which have set up as Internet Service Providers (ISPs), whose sole purpose is to act as routers, or internet telephone exchanges, to facilitate the connection to the internet of private individuals or small businesses who do not want to be, or cannot afford to be online all the time.
Your typical private individual or small company will want to have a connection, but not pay the high cost of being permanently online. There is a simple way round this. They merely pay an ISP to have access to the internet through the online computer belonging to the ISP. They ring in to their ISP whenever they want to get online. When they have completed their business, they log off again.
So you have a central hub of computers permanently connected, and a periphery of computers that log on and off as required. This means the actual number of computers physically interconnected at any one time will vary.